1. Field of the Invention
This invention relates to a disc cartridge, having a disc-shaped recording medium, such as an optical disc, housed therein, and a disc recording and/or reproducing apparatus, on which is loaded this disc cartridge.
This application claims priority based upon the Japanese Patent Applications 2003-281390 and 2003-281393, filed in Japan on Jul. 28, 2003, and the Japanese Patent Application 2004-140490, filed in Japan on May 10, 2004. These applications are incorporated in their entirety by reference herein.
2. Description of Related Art
Up to now, a disc cartridge, having a disc-shaped recording medium, such as an optical disc, rotatably housed therein, and which is loaded on a disc recording and/or reproducing apparatus, as the disc-shaped recording medium is housed therein, has been in use extensively. This sort of the disc cartridge, comprising a disc-shaped recording medium, housed in a main cartridge body unit, can be loaded/unloaded for the disc recording and/or reproducing apparatus, with the disc-shaped recording medium being in a protected state.
Meanwhile, the size of the disc cartridge has to be reduced to as small a value as possible, in keeping with the size of the disc-shaped recording medium, housed therein, in order to reduce the size of the disc recording and/or reproducing apparatus, employing the disc cartridge, in order to provide for facilitated handling of the disc cartridge, and in order to save the cartridge material and hence the production cost.
A disc cartridge, reduced in size in keeping with the size of the disc-shaped recording medium, housed therein, is disclosed in, for example, the Japanese Laid-Open Patent Publication H11-353845 (Patent Publication 1).
In this disc cartridge, disclosed in the Patent Publication 1, the lateral side thereof corresponding to the inserting end into the recording and/or reproducing apparatus, is substantially arcuate-shaped to reduce the size of the disc cartridge per se.
It is desired to reduce the disc cartridge, having housed therein the disc-shaped recording medium, further in size through realization of high recording density of the disc-shaped recording medium. Moreover, it is desired to reduce the disc cartridge further in size for further reducing the size of the disc cartridge.
Meanwhile, disc cartridges, inclusive of one described in Patent Publication 1, are loaded in position in a cartridge loading section in a recording and/or reproducing apparatus along the planar direction and along the height-wise direction. This setting of the loading position is by engaging a positioning reference pin provided on the cartridge loading section in a positioning reference hole provided to the disc cartridge.
In conventional disc cartridges, this positioning reference hole is provided in an area offset from an area in which is located the disc-shaped recording medium housed therein. The purpose for doing this is to enable the positioning reference hole to be deeper in depth, in order that, for reliable engagement between a positioning reference pin provided to the recording and/or reproducing apparatus and the positioning reference hole, a sufficient amount of relative movement will be afforded for the positioning reference pin and the positioning reference hole to be engaged with each other.
If the positioning reference hole is provided outside the area where there is housed the disc-shaped recording medium, the disc cartridge cannot be further reduced in size. On the other hand, with the recording and/or reproducing apparatus, employing this sort of the disc cartridge, the apparatus itself cannot be reduced in size because the positioning reference pin needs to be provided on an outer side of a casting area of the disc-shaped recording medium, even though the disc drive unit for rotationally driving the disc-shaped recording medium for recording and/or reproduction is reduced in size so as to be accommodated in such casting area.
In currently widely used disc cartridges, inclusive of one described in Patent Publication 1, the recording and/or reproducing aperture for exposing a signal recording area of the disc-shaped recording medium to outside is formed within the plane of the main cartridge body unit. In this type of the disc cartridge, the signal recording area cannot be efficiently extended as far as the outer rim of the disc-shaped recording medium, because it is necessary to cause movement of the recording and/or reproducing head within the range of the recording and/or reproducing aperture formed within the plane of the main cartridge body unit in order to scan the signal recording area of the disc-shaped recording medium.
If an optical disc, in which attempts have been made to improve the recording density, is used as a recording medium, an optical pickup having an objective lens with a high numerical aperture (NA) is used as a recording and/or reproducing head, for further reducing the beam diameter of the light beam scanning the signal recording area of the optical disc. If such optical pickup is used, the optical pickup needs to be approached to the optical disc. For approaching the optical pickup to the optical disc, at least a portion of the optical pickup needs to be intruded into the disc cartridge. Should the optical pickup be partially intruded into the disc cartridge, limitations are imposed on the area of possible movement of the optical pickup, with the result that the signal recording area cannot efficiently be extended as far as the outer rim of the disc-shaped recording medium.
Since it is difficult with the conventional disc cartridge to extend the signal recording area of the disc-shaped recording medium, housed therein, it is difficult to enlarge the recording capacity as it is attempted to reduce the size of the disc-shaped recording medium.